3 \page adding_quadratic_elements_page Adding Quadratic Elements
5 \n MESH module allows you to work with <b>Quadratic Elements</b>.
7 Quadratic elements are defined by the same corner nodes as the
8 corresponding linear ones, but in addition they have \a midside nodes
9 located between the corner nodes on element sides.
11 If a quadratic 2D element has an additional node at the
12 element center, it is a bi-quadratic element (both TRIA7 and
13 QUAD9 elements are supported). If a quadratic hexahedral element has 7
14 additional nodes: at the element center and at the center of each
15 side, it is a tri-quadratic element (or HEXA27).
17 The convention of nodal connectivity of elements used in SALOME is
18 the MED library convention. You can consult the description of nodal
19 connectivity of elements in the documentation on MED library or
20 <a href="http://www.code-aster.org/outils/med/html/connectivites.html">
23 There are several ways to create quadratic elements in your mesh:
24 - manually (this way is described below);
25 - use \ref quadratic_mesh_anchor "Quadratic Mesh" hypothesis to
26 generate a quadratic mesh on your geometry;
27 - convert an existing linear mesh to a quadratic one
28 (see \ref convert_to_from_quadratic_mesh_page).
30 <em>To add a quadratic element to your mesh:</em>
32 <li>Select your mesh in the Object Browser or in the 3D viewer.</li>
34 <li>From the \b Modification menu choose the \b Add item and select
37 \image html image152.png
39 \note All dialogs for adding quadratic element to the mesh
40 provide the possibility to automatically add an element
41 to the specified group or to create the group anew using
42 <b>Add to group</b> box, that allows choosing an existing group for
43 the created node or element or giving the name to a new group. By
44 default, the <b>Add to group</b> check box is switched off. If the user
45 swiches this check box on, the combo box listing all currently
46 existing groups of the corresponding type becomes available. By
47 default, no group is selected. In this case, when the user presses
48 <b>Apply</b> or <b>Apply & Close</b> button, the warning message box
49 informs the user about the necessity to input a new group name. The
50 combo box lists groups of all the
51 \ref grouping_elements_page "three types": both
52 \ref standalone_group "standalone groups",
53 \ref group_on_filter "groups on filter", and
54 \ref group_on_geom "groups on geometry". If the user chooses a
55 group on geometry or on filter, he is warned and proposed to
56 convert this group to standalone.
57 If the user rejects conversion operation, it is cancelled and
58 a new quadratic element is not created.
61 To create any <b>Quadratic Element</b> specify the nodes which will
62 form your element by selecting them in the 3D viewer with pressed
63 Shift button and click \a Selection button to the right of
64 <b>Corner Nodes</b> label. Their numbers will appear in the dialog box
65 as <b>Corner Nodes</b> (alternatively you can just input numbers in
66 this field without selection; note that to use this way the mesh
67 should be selected before invoking this operation). The edges formed
68 by the corner nodes will appear in the table. To define the middle
69 nodes for each edge, double-click on the respective field and input
70 the number of the node (or pick the node in the viewer). For
71 bi-quadratic and tri-quadratic elements, your also need to specify
73 As soon as all needed nodes are specified, a preview of a new
74 quadratic element will be displayed in the 3D viewer. Then
75 you will be able to click \b Apply or <b>Apply and Close</b> button to
76 add the element to the mesh.
80 \b Reverse button reverses the element.
